Electrophoretic comparison of enzymes as a chemotaxonomic aid among Aspergillus taxa: (3) The identity of the xerophilic species A. penicillioides in subgenus Aspergillus section Restricti.

Abstract

The identity of the xerophilic species Aspergillus penicillioides and related taxa has been studied chemotaxonomically using polyacrylamide slab gel electrophoresis. In a dendrogram based on the calculated similarity values of five enzymes, 14 isolates of A. penicillioides in subgenus Aspergillus section Restricti and 28 isolates of related taxa in subgenus Aspergillus formed 22 clusters at a 60% similarity level. A. penicillioides isolates were scattered over the 11 clusters. In the ubiquinone systems, all isolates of A. penicillioides, including IFO 8155 (originally described as A. vitricolae [sic]), had the Q-9 system, which was the same ubiquinone system as Eurotium spp. A case study based on comparisons between the similarity values in enzyme patterns and the homology values in DNA relatedness in subgenus Circumdati section Flavi clearly indicates that Aspergillus isolates at a 60% or greater similarity level in enzyme patterns are considered to be conspecific. According to this guideline, A. penicillioides isolates are extremely diverse and presumably assigned to several species and we revive the name A. vitricola for IFO 8155 (ex holotype). Further molecular systematic studies are needed to clarify the identity and speciation of A. penicillioides.